1. Field of the Invention
The present invention relates to a method and system for authenticating a mobile terminal. More particularly, the present invention relates to a method and system for effectively authenticating a mobile terminal when the mobile terminal performs a handover.
2. Description of Related Art
A mobile terminal must perform a full authentication procedure which involves multiple round-trips to a remote home Authentication, Authorization, and Accounting (AAA) server via a NAS. This process is performed according to a conventional art, every time a mobile terminal (MT) moves to a domain of another Network Access Server (NAS). The authentication procedures of the mobile terminal, which are performed upon handover, increase handover latency.
Latest network access authentication protocols, for example, Protocol for carrying Authentication for Network Access (PANA) and World Interoperability for Microwave Access (WiMAX), among others, have already optimized intra-NAS mobility. No additional authentication with the home AAA server is required once the mobile terminal is authenticated by the NAS. As long as the MT performs handover to another access node, for example, a base station, under the same NAS, no additional authentication with the home AAA server will be required.
Accordingly, efforts to optimize the intra-NAS mobility are being made. Also, according to another conventional art, a new NAS obtains session keys from a previous NAS to quickly authenticate the mobile terminal. The present scheme requires inter-NAS business relation and security association, which cannot be guaranteed for all circumstances. For example, it is difficult to exchange a session key corresponding to security information between NASs which are operated by different operators.
Also, another scheme is that the mobile terminal performs an authentication procedure with potential target NASs. In the present scheme, the mobile terminal must be familiar with the potential target NASs. Also, since a specific protocol, PANA, must be utilized, cost of over-the-air signaling is increased.
Accordingly, there is a need for an improved system and method for reducing handover latency by eliminating a necessity for information exchange between a backend authentication server and a NAS which authenticate a mobile terminal over a long period of time.